Problem: Simplify the following expression: $x = \dfrac{r - 1}{4r - 9} + \dfrac{7r + 10}{4r - 9}$
Explanation: Since the expressions have the same denominator we simply combine the numerators: $x = \dfrac{r - 1 + 7r + 10}{4r - 9}$ Combine like terms: $x = \dfrac{8r + 9}{4r - 9}$